This library has never been used in production and the tests while looking
awesome do not actually test what is being sent to mixpanel. The code does
appear to work and in my limmited testing I havn't encountered anything
unexpected.

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.
Please write tests for any changes and make sure they pass :)